生长激素受体敲低状态下棕榈酸通过线粒体途径加重肝细胞凋亡  

Palmitic acid increases apoptosis by mitochondrial pathway in hepatocytes with growth hormone deficiency

作　　者：王蕴婷 郑晓雅[1] 陈月 钱文杰 伍询 任伟[1] WANG Yunting;ZHENG Xiaoya;CHEN Yue;QIAN Wenjie;WU Xun;REN Wei(Department of Endocrinology,the First Affiliated Hospital of Chongqing Medical University,Chongqing,400016,China)

机构地区：[1]重庆医科大学附属第一医院内分泌内科,重庆400016

出　　处：《第三军医大学学报》2021年第21期2366-2374,共9页Journal of Third Military Medical University

摘　　要：目的研究生长激素受体(growth hormone receptor,GHR)敲低后棕榈酸(palmitic acid,PA)增加肝细胞的脂质沉积及其机制。方法构建稳定低表达GHR的永生化肝L02细胞株,用不同浓度PA(0、75、150、300μmol/L)和不同时间(12、24、48 h)处理细胞,检测细胞活力。将实验分为GHR敲低(shRNAGHR)组和空载病毒(Vector)组,分别给予PA干预,油红“O”、BODIPY荧光染色观察细胞内脂质沉积;流式细胞仪检测细胞凋亡和活性氧(reactive oxygen species,ROS)水平;JC-1检测线粒体膜电位的变化;MitoSox荧光检测线粒体内ROS水平,Western blot检测经典线粒体凋亡通路相关蛋白表达;靶向线粒体抗氧化剂MitoTEMPO预处理细胞,观察PA诱导的ROS水平变化及凋亡情况。结果PA抑制L02细胞存活率并呈浓度依赖性。与对照组相比,150μmol/L PA处理细胞12、24、48 h,GHR敲低组细胞内ROS水平以及线粒体内ROS水平显著升高,细胞凋亡增加。油红“O”、BODIPY荧光染色均证实GHR敲低组细胞在相同PA刺激下更易发生脂质聚集。GHR敲低组细胞线粒体凋亡通路相关蛋白细胞色素c、Cleaved-Caspase 9、Cleaved-Caspase3、PARP蛋白水平显著高于Vector组。差异均具有统计学意义(P<0.05)。采用靶向线粒体抗氧化剂MitoTEMPO预处理细胞后,敲低组肝L02细胞凋亡有明显改善。结论生长激素受体敲低状态下会加重肝细胞脂质沉积和肝细胞凋亡,PA通过线粒体/ROS途径发挥重要作用。Objective To investigate the specific molecular mechanisms of palmitic acid(PA)-induced lipid deposition in cultured hepatocytes with knockdown of growth hormone receptor(GHR).Methods Hepatic L02 cells were treated with different concentrations of PA(0,75,150 and 300μmol/L)for 12,24,and 48 h,respectively,and cell viability was measured.Then the L02 cells were transinfected with GHR-lentiviral vector(shRNAGHR group)or control vector(vector group).Oil red"O"staining and boron-dipyrromethene(BODIPY)fluorescence staining were used to observe lipid deposition.Flow cytometry was employed to detect the apoptosis and production of reactive oxygen species(ROS).JC-1 mitochondrial membrane potential assay was applied to detect the changes in membrane potential.MitoSox fluorescence was used to detect mitochondrial ROS level.Western blotting was carried out to measure mitochondrial-mediated apoptotic protein expression.After pretreated with targeted mitochondrial antioxidant,mitoTEMPO,the cells were further observed whether it could offset PA-induced changes in ROS level and apoptosis.Results PA inhibited the survival rate of the L02 cells in a concentration-dependent manner.Compared with the control group,treatment of 150μumol/L PA for 12,24,and 48 h resulted in significantly increased intracellular ROS level,mitochondrial ROS level and cell apoptosis in the shRNAGHR.Oil red"O"staining and BODIPY fluorescence confirmed that shRNAGHR group was more prone to lipid deposition with same dose of PA stimulation.Western blotting showed the levels of cytochrome C protein,Cleaved-Caspase 9,Cleaved-Caspase 3,and polymerase(PARP)were significantly higher in the shRNAGHR group than the vector group(P<0.05).Pretreatment of targeted mitochondrial antioxidant mitoTEMPO significantly ameliorated shRNAGHR induced cells apoptosis.Conclusion Knockdown of GHR aggravates lipid deposition and apoptosis in hepatocytes,and PA plays an important role in the process through mitochondria/ROS pathway.

关 键 词：生长激素受体敲低 线粒体 活性氧 细胞凋亡 

分 类 号：R347.511[医药卫生—基础医学] R363.21